This invention relates to a cylinder lock, and particularly to a cylinder lock which includes axially moved locking members and radially moved locking members and which is operated by a key having axially extending projections and radially extending projections.
Various cylinder locks exist in the art. Some of them include radially extending tumblers to lock a plug against rotation relative to a cylindrical housing. Some cylinder locks include locking pieces which lock a cylindrical plug against rotation relative to a cylindrical shell and which can be moved axially by means of a key to their unlocking position. Examples of the latter are described in U.S. Pat. Nos. 3,878,700, 2,391,834, 1,494,765, 2,557,028, and 3,408,840, Netherlandish Patent No. 6,701,370, and Italian Patent No. 685948.
U.S. patent application No. 697,297 which was filed by the inventor of this application and which is now abandoned, discloses a cylinder lock shown in FIG. 1. The lock includes a cylindrical shell 1', a core assembly 2', locking pieces 3' axially movable in the grooves of the core assembly 2', and radial tumbler pins 4'. Each locking piece 3 has an inward projection 31' to slide in each slot 21' of the core assembly 2'. The locking pieces 3' achieve their unlocking position when their peripheral grooves 32' are aligned circumferentially with the peripheral grooves 22' of the core assembly 2'. It was found by the applicant that such a lock can be picked easily by an intruder. This is because the projection 31' of the locking pieces can be moved not only inwardly, but also slightly laterally so that a person may easily feel whether or not the locking pieces are in their unlocking position. Therefore, it is desirable to provide an improvement for such a lock.